If it is judged by a signal from a first signal processing unit that a signal of a first communication system is not received and it is judged by a signal from a second signal processing unit that a signal of a second communication system is received, wireless communication is performed by the second communication system. If it is judged that the signals of the first and the second communication systems are received, a system judging unit judges which communication system is to be used for the wireless communication, based on the signals from the first signal processing unit and the second signal processing unit. If the wireless communication is to be performed by the first communication system, diversity reception or transmission is performed by first and second antenna elements.